Method and apparatus for performing random access

ABSTRACT

Systems, apparatuses, and methods for wireless communications are provided. A method may comprise receiving, by a wireless device from a base station, one or more messages comprising downlink control information (DCI) associated with a DCI format; determining that a first field of the DCI corresponds to a predefined value; determining that, based on the first field corresponding to the predefined value, the DCI is for a random access procedure associated with a physical downlink control channel (PDCCH) order; determining, based on the determining that the DCI is for a random access procedure associated with a PDCCH order and based on a plurality of fields of the DCI, a random access channel (RACH) occasion; and transmitting, based on the RACH occasion, a random access preamble.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2018-0018724 filed on Feb. 14, 2018, which is herebyincorporated by reference in its entirety.

BACKGROUND 1. Field

The present disclosure relates to wireless communications. A message(e.g., a physical downlink control channel (PDCCH) order) may be usedfor a random access procedure available for an initial system accessand/or various purposes (e.g., uplink synchronization (UL sync),handover, beam failure recovery, radio resource recovery (RRC)establishment, etc.) in a new radio (NR) system.

2. Discussion of the Background

The IMT (International Mobile Telecommunication) frameworks andstandards have been developed by ITU (International TelecommunicationUnion) and, recently, the 5th generation (5G) communication has beendiscussed through a program called “IMT for 2020 and beyond”.

In order to satisfy requirements from “IMT for 2020 and beyond”, thediscussion is in progress about a way for enabling the 3rd GenerationPartnership Project (3GPP) New Radio (NR) system to support variousnumerologies by taking into consideration various scenarios, variousservice requirements, potential system compatibility.

Also, the NR system considers transmission of a physical signal/channelthrough a plurality of beams to overcome a poor channel environment,such as high pathloss occurring in a relatively high carrier frequency,phase-noise, and frequency offset.

SUMMARY

Systems, apparatus, and methods are described for wirelesscommunications. A downlink control information (DCI) format about aphysical downlink control channel (PDCCH) order may be determined by abase station, for example, an evolved node base (eNode B). Signalingschemes for initializing a new radio contention free random access (NRCFRA) are described.

The present disclosure also provides a method and apparatus ofdetermining DCI format including control information for initializing aCFRA.

The present disclosure also provides a method and apparatus of setting aDCI format that may provide a user equipment (UE) with controlinformation different from control information used for general datascheduling.

A method may comprise receiving, by a wireless device from a basestation, one or more messages comprising downlink control information(DCI) associated with a DCI format; determining that a first field ofthe DCI corresponds to a predefined value; determining that, based onthe first field corresponding to the predefined value, the DCI is for arandom access procedure associated with a physical downlink controlchannel (PDCCH) order; determining, based on the determining that theDCI is for a random access procedure associated with a PDCCH order andbased on a plurality of fields of the DCI, a random access channel(RACH) occasion; and transmitting, based on the RACH occasion, a randomaccess preamble.

A method may comprise determining, by a base station, a random accesschannel (RACH) occasion for a wireless device, the RACH occasion beingassociated with a synchronization signal/physical broadcast channel(SS/PBCH) block; generating downlink control information (DCI)corresponding to a DCI format, the DCI comprising: a first field havinga predefined value indicating that the DCI is for a random accessprocedure associated with a physical downlink control channel (PDCCH)order; an SS/PBCH block index field having a value indicating theSS/PBCH block; and an index field having a value indicating one or moreRACH occasions, the RACH occasion for the wireless device beingindicated by the values of the SS/PBCH block index field and the indexfield; transmitting, to the wireless device, the DCI; and receiving,from the wireless device and based on the RACH occasion, a random accesspreamble.

A method may comprise receiving, by a wireless device from a basestation, one or more messages comprising downlink control information(DCI); determining that the DCI corresponds to DCI format 1_0;determining that, based on a first field of the DCI format 1_0, the DCIis for a random access procedure associated with a physical downlinkcontrol channel (PDCCH) order; determining, based on a synchronizationsignal/physical broadcast channel (SS/PBCH) block index field of the DCIand based on an index field associated with one or more random accesschannel (RACH) occasions, a RACH occasion; and transmitting, based onthe RACH occasion, a random access preamble.

A DCI format comprising control information of a CFRA initialization maybe provided. A base station may indicate transmission resources for apreamble for the CFRA based on the control information of the DCIformat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a method of determining an uplinktransmission timing based on a downlink reception timing.

FIG. 2 illustrates an example of a resource grid and a resource block.

FIG. 3 illustrates an example of a contention-based random accessprocedure in a new radio (NR) system.

FIG. 4 illustrates an example of a method of indicating a PRACH resource(also referred to as a PRACH resource indication method) in a syncsignal block (SSB)-PRACH occasion mapping period.

FIG. 5 illustrates an example of a PRACH resource indication method inan SSB-PRACH mapping period.

FIG. 6 illustrates an example of a PRACH resource indication method inan SSB-PRACH mapping period.

FIG. 7 illustrates an example of a PRACH resource indication method inan SSB-PRACH mapping period.

FIG. 8 illustrates an example of a PRACH resource indication method inan SSB-PRACH mapping period.

FIG. 9 illustrates an example of a PRACH resource indication method inan SSB-PRACH mapping period.

FIG. 10 illustrates an example of a PRACH resource indication method.

FIG. 11 illustrates an example of a PRACH resource indication method fora user equipment (UE) to which four preamble transmissions are set.

FIG. 12 illustrates an example of a PRACH resource indication method fora UE to which four preamble transmissions are set.

FIG. 13 is a block diagram illustrating an example of a UE and anevolved node base (eNode B).

DETAILED DESCRIPTION

Various examples will be described more fully hereinafter with referenceto the accompanying drawings. Throughout the drawings and the detaileddescription, unless otherwise described, the same drawing referencenumerals are understood to refer to the same elements, features, andstructures. In describing the examples, detailed description on knownconfigurations or functions may be omitted for clarity and conciseness.

Further, the terms, such as first, second, A, B, (a), (b), and the likemay be used herein to describe elements in the description herein. Theterms are used to distinguish one element from another element. Thus,the terms do not limit the element, an arrangement order, a sequence orthe like. It will be understood that when an element is referred to asbeing “on”, “connected to” or “coupled to” another element, it can bedirectly on, connected or coupled to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly on,” “directly connected to” or “directly coupled to”another element, there are no intervening elements present.

In the described exemplary system, although methods are described basedon a flowchart as a series of steps or blocks, aspects of the presentdisclosure are not limited to the sequence of the steps and a step maybe executed in a different order or may be executed in parallel withanother step. In addition, it is apparent to those skilled in the artthat the steps in the flowchart are not exclusive, and another step maybe included or one or more steps of the flowchart may be omitted withoutaffecting the scope of the present disclosure. When an implementation isembodied as software, the described scheme may be embodied as a module(process, function, or the like) that executes the described function.The module may be stored in a memory and may be executed by a processor.The memory may be disposed inside or outside the processor and may beconnected to the processor through various well-known means.

Further, the description described herein is related to a wirelesscommunication network, and an operation performed in a wirelesscommunication network may be performed in a process of controlling anetwork and transmitting data by a system that controls a wirelessnetwork, e.g., a base station, or may be performed in a user equipmentconnected to the wireless communication network.

It is apparent that various operations performed for communication witha terminal in a network including a base station and a plurality ofnetwork nodes may be performed by the base station or by other networknodes in addition to the base station. Here, the term ‘base station(BS)’ may be interchangeably used with other terms, for example, a fixedstation, a Node B, eNodeB (eNB), gNodeB (gNB), and an access point (AP).Also, the term ‘terminal’ may be interchangeably used with other terms,for example, user equipment (UE), a mobile station (MS), a mobilesubscriber station (MSS), a subscriber station (SS), and a non-APstation (non-AP STA).

Herein, transmitting or receiving a channel includes a meaning oftransmitting or receiving information or a signal through thecorresponding channel. For example, transmitting a control channelindicates transmitting control information or a signal through thecontrol channel. Likewise, transmitting a data channel indicatestransmitting data information or a signal through the data channel.

In the following description, a system to which various examples of thepresent disclosure are applied may be referred to as a New Radio (NR)system to be distinguished from other existing systems. The NR systemmay include one or more features defined by TS38 series of the thirdpartnership project (3GPP) specification. However, the scope of thepresent disclosure is not limited thereto or restricted thereby. Inaddition, although the term ‘NR system’ is used herein as an example ofa wireless communication system capable of supporting a variety ofsubcarrier spacings (SCSs), the term ‘NR system’ is not limited to thewireless communication system for supporting a plurality of subcarrierspacings.

FIG. 1 illustrates an example of describing a timing between a downlinkframe and an uplink frame.

Referring to FIG. 1, a timing or a time structure between a downlinkframe for downlink transmission and an uplink frame for uplinktransmission has T_(f)=(Δf_(max)N_(f)/100)·T_(s)=10 ms. Here, tensubframes corresponding to T_(sf)=(Δf_(max)N_(f)/1000)·T_(s)=1 msconstitute a single frame. A transmission timing of an uplink frame i isdetermined by a UE according to T_(TA)=N_(TA)T_(s) based on a receptiontiming of a downlink frame i. Here, a value of N_(TA) denotes a TA valueindicated by an eNode B and T_(s) denotes a minimum time unit sample ofan NR system.

FIG. 2 illustrates an example of a resource grid and a resource blockaccording to an embodiment.

Referring to FIG. 2, a resource element within a resource grid isindexed based on each subcarrier spacing. A single resource grid may begenerated per subcarrier spacing of each antenna port anduplink/downlink (UL/DL) transmission and reception may be performedbased on the corresponding resource grid.

A single resource block is configured on a frequency domain using 12resource elements (N_(sc) ^(RB)=12) and configures an index n_(PRB) fora single resource block every 12 resource elements. An index of theresource block may be used in a specific frequency band or systembandwidth. Here, n_(PRB) may be represented as the following Equation 1.

$\begin{matrix}{n_{PRB} = \left\lfloor \frac{k}{N_{sc}^{RB}} \right\rfloor} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Also, for example, numerologies may be defined based on a subcarrierspacing, a cyclic prefix (CP) length, a number of orthogonal frequencydivision multiplexing (OFDM) symbols per slot, etc., in an OFDM system,as shown in Table 1. Since the NR system is to be designed to meetvarious services and requirements, the numerologies that defineresources of a physical layer may be variously configured and are notlimited to the aforementioned embodiment.

TABLE 1 μ Δf = 2^(μ) · 15 [kHz] Cyclic Prefix (CP) 0 15 Normal 1 30Normal 2 60 Normal, Extended 3 120 Normal 4 240 Normal 5 480 Normal

A normal slot may be defined as a basic time unit used to transmit asingle piece of data and control information in the NR system. A lengthof the normal slot may basically include 14 OFDM symbols. Dissimilar toa slot, a subframe may have an absolute time length corresponding to 1ms in the NR system and may be used as a reference time for a length ofanother time section. For example, a time section, such as a long termevolution (LTE) subframe for coexistence of LTE and NR, may be requiredfor an NR standard.

A non-slot refers to a slot having a number of symbols less by at leastone symbol than that of the normal slot and is introduced to basicallyprovide a low delay time of a ultra-reliable and low latencycommunications (URLLC) service. For example, a non-slot with a length of1 OFDM symbol may be considered based on a frequency range, for example,in a frequency range of 60 gigahertz (GHz) or more. However, a number ofOFDM symbols used to define the non-slot may include at least two OFDMsymbols and the range thereof may be configured with a mini-slot lengthup to a normal slot length −1. Generally, the range thereof is limitedto 2, 4, or 7 symbols.

In the case of a number N_(slot) ^(sy mb, μ) of OFDM symbols per slotaccording to each subcarrier spacing setting μ and a normal CP, thefollowing Table 2, similar to Table 1, provides a number of OFDM symbolper slot according to each subcarrier spacing value, a number of slotsper frame, and a number of slots per subframe based on 14 normal slots.

TABLE 2 μ N_(symbol) ^(slot) N_(slot) ^(frame,u) N_(slot) ^(subframe,u)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16 5 14 320 32

Also, in the case of the number N_(slot) ^(sy mb, μ) of OFDM symbols perslot according to each subcarrier spacing setting μ and an extended CP,the following Table 3, similar to Table 2, provides the number ofsymbols per slot, the number of slots per frame, and the number of slotsper subframe based on 12 normal slots in the case of the extended CPthat follows 60 kHz subcarrier spacing corresponding to μ=2.

FIG. 3 illustrates an example of a contention-based random accessprocedure in a new radio (NR) system according to an embodiment.

Here, referring to FIG. 3, in the NR system, the contention-based randomaccess procedure may be performed in order of the following Step 1 toStep 4:

-   -   Step 1: Preamble transmission;    -   Step 2: Random access response;    -   Step 3: Layer 2/Layer 3 (L2/L3) message;    -   Step 4: Contention resolution message.

Here, the aforementioned random access (RA) procedure is initiated bythe following trigger event and an initialization operationcorresponding thereto. For example, a contention-free random access(CFRA) procedure performs only the aforementioned Step 1 and Step 2.That is, since the CFRA procedure is not a contention-based procedure,the aforementioned Step 3 and Step 4 are not required. Herein, apreamble transmission represents a transmission of a preamble and thus,a plurality of preamble transmissions also represents transmissions of aplurality of preambles.

For example, initialization of the RA procedure may be performed asfollows:

-   -   PDCCH order,    -   MAC sublayer,    -   RRC sublayer, or    -   Beam failure (BF) indication from PHY.

A relationship between a cause that triggers a random access of the NRsystem and a corresponding event may be represented by the followingTable 3:

TABLE 3 Event Initiated by Note Initial access from RRC_IDLE MACsublayer RRCConnectionRequest triggers R-BSR RRC Connection Re- MACsublayer RRCConnectionReestablishmentRequest establishment triggersR-BSR Handover MAC sublayer RRCConnectionReconfigurationCompletetriggers R-BSR DL data arrival PDCCH order NW triggers random access ULdata arrival MAC sublayer New data arrival triggers R-BSR PositioningPDCCH order NW triggers random access PSCell management RRC sublayerR-BSR triggered by RRCConnectionReconfigurationComplete does notinitiate random access in PSCell STAG management PDCCH order NW triggersrandom access in SCell Beam Failure Beam Failure BF indication from alower layer indication On demand SI MAC sublayer RRC trigger R-BSR

Here, the RA procedure on SCell excluding a PSCell (a primary cell in amaster cell group (MCG) or a secondary cell group (SCG) fordual-connectivity) is initialized with an RA preamble index valueindicated by PDCCH order by the PDCCH order only.

Also, the following information may be provided to UEs through RRCsignaling.

-   -   Prach-ConfigIndex: indicates a set of available PRACH resources        for preamble transmission;    -   RA-PreambleInitialReceivedTargetPower: indicates initial        preamble power;    -   RSRP-ThresholdSSB: indicates a selection of associated preamble        resource and index based on a sync signal block (SSB) reference        signal received power (RSRP) value,        csirs-dedicatedRACH-Threshold: indicates a selection of        associated preamble resource and index based on a CSI-RS RSRP        value, and sul-RSRP-Threshold: an RSRP threshold for the        selection of the SS block and corresponding PRACH resource;    -   RA-PreamblePowerRampingStep: indicates a power-ramping factor;    -   RA-PreambleIndex: indicates a random access preamble index;    -   RA-PreambleTx-Max: indicates transmission of the maximum number        of preambles.

Also, a preamble index group and indices included in the correspondinggroup may be sequentially assigned per SSB depending on whether amapping relationship between a preamble transmission resource and anindex is preset per SSB. The preamble group is used for an eNode B toestimate a size of UL resource required for msg.3 transmission. That is,when preamble groups A and B are set to a UE, the UE selects a preambleindex in the group B and transmits a preamble during an RA procedurecorresponding to a specific msg.3 size (ra-Msg3 SizeGroupA) or more.When the eNode B verifies that the preamble of the group B is received,the eNode B includes size information of the UL resource required formsg.3 transmission in msg.2 that is response information for thepreamble and perform scheduling for the UE.

-   -   Size of RA window: is indicated to the UE by a number of slots    -   Preamble index set and for SI request and corresponding PRACH        resource (if necessary)    -   Beam failure request response window and corresponding PRACH        resource (if necessary)    -   bfr-ResponseWindow: indicates a time window to monitor        response(s) on beam failure recovery request    -   Ra-ContentionResolutionWindow: indicates a size of a time window        to monitor an RA response.

To initialize the RA procedure, the UE empties an msg.3 buffer, sets apreamble transmission counter to 1, sets a preamble power rampingcounter to 1, and sets a preamble back-off to 0 ms. If a carrier onwhich the RA procedure is to be performed is explicitly signaled, the UEperforms the RA procedure on the corresponding carrier. Otherwise, if asupplement uplink (SUL) cell is set as a cell for the RA procedure andan RSRP value of DL pathloss of the corresponding cell is less than asul-RSRP threshold, the UE selects the SUL cell as a carrier forperforming the RA procedure and sets a PCMAX value for a normal carrier.

The UE sets a preamble index value through a resource selectionprocedure and determines a related next available PRACH occasion. Indetail, a method of determining a PRACH occasion determines the PRACHoccasion based on a case in which a correlation setting between an SSBblock index and the PRACH occasion is present, a case in which acorrelation setting between CSI-RS and the PRACH occasion is present, ora case in which the correlation settings are not provided to the UE. Ifthe correlation setting between the SSB or CIS-RS and the PRACH occasionis present, a related PRACH occasion is determined based on SSB orCSI-RS selected by the UE. Conversely, if the correlation setting isabsent, the UE performs a preamble transmission in the next availablePRACH occasion.

The UE performs a preamble transmission based on the selected PRACHoccasion, and a MAC layer provides a selected preamble, a related radionetwork temporary identifier (RNTI) value, a preamble index, andreceived power to a PHY layer to perform transmission of the selectedpreamble. In this manner, the UE needs to monitor reception of msg2(random access response (RAR)) information corresponding to thetransmitted preamble. Such a time section is defined as an RA window.After a desired number of symbols in which the preamble is transmitted,the UE desires to receive RAR (msg.2) and performs monitoring ofPDCCH/PDSCH (for msg.2) based on an RA-RNTI value during a period oftime corresponding to the RA window. If response information (RAPID) isincluded in the received msg.2, the UE determines that reception of theRAR is a success. Otherwise, the UE performs again the preamble resourceselection procedure to prepare for a preamble retransmission.

The UE performs msg.3 transmission based on scheduling in the receivedmsg.2 and parameter information for the msg.3 transmission. Once themsg.3 transmission is performed, the UE initiates a contentionresolution timer and performs monitoring of PDCCH (with C-RNTI) forreceiving msg.4 during an operation of the corresponding timer. If msg4is received, the UE determines that the contention resolution issuccessfully performed.

Hereinafter, a method of designing a downlink control information (DCI)format for PDCCH order through eNode B signaling for initializing an NRCFRA will be described based on the aforementioned description.

Although the following description is made based on each individualembodiment, it is provided as an example only and the followingembodiments may be combined and thereby applied.

Embodiment 1

A DCI format about PDCCH order may be designed through eNode B signalingfor initializing an NR CFRA.

In an NR system, an eNode B may instruct the UE to initialize and thenperform a RA procedure through PDCCH signaling as signaling forinitialization of the CFRA. The eNode B transmits a DCI format in thePDCCH. Here, control information for initialization of the CFRA ispresent in the corresponding DCI format and control informationdifferent from control information used for general data scheduling istransmitted to the UE using the corresponding DCI format. However, toprevent an increase in a number of times the UE performs PDCCH blinddecoding, a number of bits of the PDCCH DCI format for the CFRA may beidentical to a size of a fallback DCI format for transmitting a singletransport block (TB).

Here, the aforementioned fallback DCI format refers to a DCI formatavailable when a UE channel environment is poor in a transmission modeset for downlink or uplink data scheduling. That is, the fallback DCIformat is not a DCI format used to transmit a large amount of data suchas multiple input and multiple output (MIMO) and thus, includes arelatively small number of bits. Also, only control information forminimum data scheduling is present within the corresponding fallback DCIformat. The corresponding fallback DCI may include DCI format 0_0(downlink transmission) and DCI format 1_0 (uplink transmission).

Hereinafter, it is assumed that a size of the DCI format transmitted inPDCCH order for indicating the initialization of the CFRA proposedherein is identical to a size of the fallback DCI (e.g., DCI format 0_0or DCI format 1_0). Accordingly, in the NR system, the DCI format forPDCCH order may be configured based on the fallback DCI format.Hereinafter, features and embodiments of the DCI format of PDCCH orderfor the NR system will be described. A DCI format cyclic redundancycheck (CRC) for PDCCH order may be scrambled with a C-RNTI value and maybe indicated to the UE by the eNode B based on one of the followingembodiments.

Table 4 shows DCI format 0_0 and DCI format 1_0 based on the NR fallbackDCI format.

TABLE 4 DCI format 0_0 (UL) DCI format 1_0 (DL) Identifier for DCIformats 1 bit 1 bit Frequency domain resource ┌log₂(N_(RB)^(UL,BWP)(N_(RB) ^(UL,BWP) + 1)/2)┐ ┌log₂(N_(RB) ^(DL,BWP)(N_(RB)^(DL,BWP) + 1)/2)┐ assignment Time domain resource assignment X bits Xbits Frequency hopping flag 1 bit 1 bit Modulation and coding scheme 5bits 5 bits New data indicator 1 bit 1 bit Redundancy version 2 bits 2bits HARQ process number 4 bits 4 bits TPC command for scheduled 2 bitsx PUSCH Downlink assignment index x 2 bits TPC command for scheduled x 2bits PUCCH PUCCH resource indicator x 2 bits PDSCH-to-HARQ_feedback x 3bits iming indicator UL/SUL indicator 1 bit (in Padding bits) x

Referring to Table 4, in the NR system, the fallback DCI format uses afield about the above control information for data scheduling. To fit arelatively small size of a DCI format for a relatively great size of aDCI format among corresponding fallback DCI formats, a zero value isadded as a padding bit. When the padding bit is added in DCI format 0_0,the added padding bit may be used as a 1 bit for UL/SUL indicator.

Assuming the DCI format for PDCCH order based on the same size as thatof the fallback DCI format, the following fields may be generated. Also,an additional resource assignment method for a plurality of CFRApreamble transmissions is proposed herein.

The DCI format for PDCCH order (based on the fallback DCI format) may beused as follows:

Carrier Indicator—0 or ¾ Bits

If cross-carrier scheduling is set to the UE, a corresponding field maybe enabled with 3 or 4 bits, and otherwise, 0 bit. Alternatively;

Regardless of whether cross-carrier scheduling is set to the UE, the DCIformat for PDCCH order indicates a preamble transmission in the sameserving cell as that in which only the PDCCH is transmitted.Accordingly, in this case, “carrier indicator” field is absent.According to this setting method, since PDCCH order between a pluralityof serving cells is not indicated in an environment in which a pluralityof BWPs is set in a single serving sell, implementation in the UE may befurther easily performed.

Identifier for DCI Formats—1 bit or 2 bits

If the field is set to 1 bit, each of fallback DCI may have the samenumber of bits. Thus, a value of 0 indicates DCI format 0_0 and a valueof 1 indicates DCI format 1_0 as a field for identifying DCI format 0_0or DCI format 1_0. In this case, the eNode B may implicitly indicate tothe UE regarding whether the corresponding DCI indicates PDCCH orderbased on settings of some field values included in the DCI.

If the field is set to 2 bits (e.g., if a further larger number of bitsare used to explicitly indicate PDCCH order, the indication may beperformed as follows:

00: DCI format 0_0

01: DCI format 1_0

10: PDCCH order

11: reserved

Frequency Domain Resource Assignment—┌log₂(N_(RB) ^(UL,BWP)+1)/2┐ bits

To indicate the DCI format for PDCCH order, all of the bits are set to 0or 1. Although the frequency resource assignment field is notinformation required to indicate PDCCH order, the DCI format used totransmit the PDCCH order is based on DCI format 0_0/DCI format 1_0.Accordingly, the eNode B may indicate whether the PDCCH order is basedon DCI format 0_0/DCI format 1_0 using the aforementioned settingmethod.

Time Domain Resource Assignment—X bits

To indicate PDCCH order, all of the bits are set to 0 or 1.Alternatively;

The bits are set to indicate one of corresponding specific codepointsusing the specific codepoints unused among X bits. The time domain PUSCHresource field indicates a slot offset (K₂), a start and lengthindicator value (SLIV) of a slot, and a combination of PUSCH mappingtypes (Type A or B) through upper layer configuration. Accordingly, thebits may be set using remaining specific codepoints (i.e., reserved)among X bits as the DCI format indicator for PDCCH order. For example,if X=4 bits, and in this instance, if the bits are set as “1111” or if asingle specific value among the following codepoints (reserved) is set,the UE may verify that the received DCI relates to the PDCCH order.

TABLE 5 Time domain PUSCH resource field slot offset (K₂) SLIV PUSCHmapping type 0 1 2 Type A 1 2 4 Type A 2 3 7 Type B 3 4 9 Type B . . . .. . . . . . . . 2^(x)-2 reserved reserved reserved 2^(x)-1 reservedreserved reserved

PRACH Resource Indicator—K Bits

Within a setting combination of a PRACH configuration period and anSSB-PRACH mapping period given through the field, the eNode B indicatesa preamble transmission resource for CFRA using the following indicationmethod:

-   -   It is assumed that, if a relationship between an SS/PBCH block        index (i.e., SSB) (and/or CSI-RS index) and a PRACH occasion        (i.e., ROs in the following cases) index is established, the        corresponding UE is applied to (Case 1 in which an upper layer        configuration for SSB-PRACH-CFRA-association or        CSI-RS-PRACH-CFRA-association is present).    -   A case in which the relationship is not established (Case 2 in        which an upper layer configuration for        SSB-PRACH-CFRA-association or CSI-RS-PRACH-CFRA-association is        absent) will be further described.

Hereinafter, although description is made based on a relationshipbetween the SSB index based on SSB-PRACH-CFRA association and the PRACHoccasion for clarity of description, the proposed method may be appliedeven to a relationship between the CSI-RS index based onCSI-RS-PRACH-CFRA-association and the PRACH occasion and thereby be usedto indicate the corresponding PRACH resource.

The PRACH occasion indicates a minimum time/frequency resource forpreamble transmission. Therefore, the preamble transmission may beperformed using a maximum of 64 preamble indices based on a PRACHconfiguration of the eNode B within the corresponding time/frequencyresource. An actual location of the time/physical resource for the PRACHoccasion may be used to verify a PRACH format through a PRACHconfiguration indicator (e.g., Table 6) and radio frame(s) andsubframe(s) for the preamble transmission. The frequency resource may bedetermined based on a length of a corresponding PRACH sequence andsubcarrier spacing.

TABLE 6 Number of Number of time- PRACH n_(SFN) PRACH slots domain PRACHConfiguration Preamble modx = y Subframe Starting within a occasionswithin Index format x y number symbol subframe a RACH slot 0 0 2 1 1 — —— 1 0 2 1 4 — — — 2 0 2 1 7 — — — 3 0 1 0 1 — — — 4 0 1 0 4 — — — 5 0 10 7 — — — 6 0 1 0 1, 6 — — — 7 0 1 0 2, 7 — — — 8 0 1 0 3, 8 — — — 9 0 10 1, 4, 7 — — — 10 0 1 0 2, 5, 8 — — — 11 0 1 0 3, 6, 9 — — — 12 0 1 00, 2, 4, 6, 8 — — — 13 0 1 0 1, 3, 5, 7, 9 — — — 14 0 1 0 0, 1, 2, 3, 4,— — — 5, 6, 7, 8, 9 15 0 2 1 9 — — — 16 0 4 1 1 — — — 17 0 4 1 4 — — —18 0 4 1 7 — — — 19 0 4 1 9 — — — 20 0 8 1 1 — — — 21 0 8 1 4 — — — 22 08 1 7 — — — 23 0 8 1 9 — — — 24 0 16 1 1 — — — 25 0 16 1 4 — — — 26 0 161 7 — — — 27 0 16 1 9 — — — 28 1 2 1 1 — — — 29 1 2 1 4 — — — 30 1 2 1 7— — — 31 1 1 0 1 — — — 32 1 1 0 4 — — — 33 1 1 0 7 — — — 34 1 1 0 1, 6 —— — 35 1 1 0 2, 7 — — — 36 1 1 0 3, 8 — — — 37 1 1 0 1, 4, 7 — — — 38 11 0 2, 5, 8 — — — 39 1 1 0 3, 6, 9 — — — 40 1 2 1 9 — — — 41 1 4 1 1 — —— 42 1 4 1 4 — — — 43 1 4 1 7 — — — 44 1 4 1 9 — — — 45 1 8 1 1 — — — 461 8 1 4 — — — 47 1 8 1 7 — — — 48 1 8 1 9 — — — 49 1 16 1 1 — — — 50 116 1 4 — — — 51 1 16 1 7 — — — 52 1 16 1 9 — — — 53 2 4 0 1 0 — — 54 2 20 1 0 — — 55 2 2 0 5 0 — — 56 2 1 0 1 0 — — 57 2 1 0 5 0 — — 58 2 8 1 10 — — 59 2 16 1 1 0 — — 60 3 4 1 1 — — — 61 3 4 1 4 — — — 62 3 4 1 7 — —— 63 3 4 1 9 — — — 64 3 8 1 1 — — — 65 3 8 1 4 — — — 66 3 8 1 7 — — — 673 16 1 1 — — — 68 3 16 1 4 — — — 69 3 16 1 7 — — — 70 3 16 1 9 — — — 713 2 1 1 — — — 72 3 2 1 4 — — — 73 3 2 1 7 — — — 74 3 1 0 1 — — — 75 3 10 4 — — — 76 3 1 0 7 — — — 77 3 1 0 1, 6 — — — 78 3 1 0 2, 7 — — — 79 31 0 3, 8 — — — 80 3 1 0 1, 4, 7 — — — 81 3 1 0 2, 5, 8 — — — 82 3 1 0 3,6, 9 — — — 83 3 1 0 0, 2, 4, 6, 8 — — — 84 3 1 0 1, 3, 5, 7, 9 — — — 853 1 0 0, 1, 2, 3, 4, — — — 5, 6, 7, 8, 9 86 3 2 1 9 — — — 87 88 89 90 9192 A1 16 0 4, 9 0 1 6 92 A1 16 1 4 0 2 6 93 A1 8 0 4, 9 0 1 6 94 A1 8 14 0 2 6 95 A1 4 0 4, 9 0 1 6 96 A1 4 0 4 0 2 6 97 A1 4 1 4, 9 0 1 6 98A1 2 0 4, 9 0 1 6 99 A1 2 0 1 0 2 6 100 A1 2 0 4 0 2 6 101 A1 2 0 7 0 26 102 A1 1 0 1 0 2 6 103 A1 1 0 4 0 1 6 104 A1 1 0 7 0 2 6 105 A1 1 0 1,6 0 1 6 106 A1 1 0 2, 7 0 2 6 107 A1 1 0 4, 9 0 1 6 108 A1 1 0 1, 4, 7 02 6 109 A1 1 0 0, 2, 4, 6, 8 0 2 6 110 A1 1 0 0, 1, 2, 3, 4, 0 2 6 5, 6,7, 8, 9 111 A1 1 0 1, 3, 5, 7, 9 0 2 6 112 A2 16 1 2, 6, 9 0 1 3 113 A216 1 4 0 2 3 114 A2 8 1 2, 6, 9 0 1 3 115 A2 8 1 4 0 2 3 116 A2 4 0 2,6, 9 0 1 3 117 A2 4 0 4 0 2 3 118 A2 2 1 2, 6, 9 0 1 3 119 A2 2 0 1 0 23 120 A2 2 0 4 0 2 3 121 A2 2 0 7 0 2 3 122 A2 1 0 1 0 2 3 123 A2 1 0 40 1 3 124 A2 1 0 7 0 2 3 125 A2 1 0 1, 6 0 1 3 126 A2 1 0 2, 7 0 2 3 127A2 1 0 4, 9 0 1 3 128 A2 1 0 1, 4, 7 0 2 3 129 A2 1 0 0, 2, 4, 6, 8 0 23 130 A2 1 0 0, 1, 2, 3, 4, 0 2 3 5, 6, 7, 8, 9 131 A2 1 0 1, 3, 5, 7, 90 2 3 132 A3 16 1 4, 9 0 1 2 133 A3 8 1 4, 9 0 1 2 134 A3 4 0 4, 9 0 1 2135 A3 16 1 4 0 2 2 136 A3 8 1 4 0 2 2 137 A3 4 0 4 0 2 2 138 A3 2 1 2,6, 9 0 2 2 139 A3 2 0 1 0 2 2 140 A3 2 0 4 0 2 2 141 A3 2 0 7 0 2 2 142A3 1 0 1 0 2 2 143 A3 1 0 4 0 1 2 144 A3 1 0 7 0 2 2 145 A3 1 0 1, 6 0 12 146 A3 1 0 2, 7 0 2 2 147 A3 1 0 4, 9 0 1 2 148 A3 1 0 1, 4, 7 0 2 2149 A3 1 0 0, 2, 4, 6, 8 0 2 2 150 A3 1 0 0, 1, 2, 3, 4, 0 2 2 5, 6, 7,8, 9 151 A3 1 0 1, 3, 5, 7, 9 0 2 2 152 B1 16 0 4, 9 0 1 7 153 B1 16 1 40 2 7 154 B1 8 0 4, 9 0 1 7 155 B1 8 1 4 0 2 7 156 B1 4 0 4, 9 0 1 7 157B1 4 0 4 0 2 7 158 B1 4 1 4, 9 0 1 7 159 B1 2 0 4, 9 0 1 7 160 B1 2 0 10 2 7 161 B1 2 0 4 0 2 7 162 B1 2 0 7 0 2 7 163 B1 1 0 1 0 2 7 164 B1 10 4 0 1 7 165 B1 1 0 7 0 2 7 166 B1 1 0 1, 6 0 1 7 167 B1 1 0 2, 7 0 2 7168 B1 1 0 4, 9 0 1 7 169 B1 1 0 1, 4, 7 0 2 7 170 B1 1 0 0, 2, 4, 6, 80 2 7 171 B1 1 0 0, 1, 2, 3, 4, 0 2 7 5, 6, 7, 8, 9 172 B1 1 0 1, 3, 5,7, 9 0 2 7 173 B4 16 0 4, 9 0 2 1 174 B4 16 1 4 0 2 1 175 B4 8 0 4, 9 02 1 176 B4 8 1 4 0 2 1 177 B4 4 0 4, 9 0 2 1 178 B4 4 0 4 0 2 1 179 B4 41 4, 9 0 2 1 180 B4 2 0 4, 9 0 2 1 181 B4 2 0 1 0 2 1 182 B4 2 0 4 0 2 1183 B4 2 0 7 0 2 1 184 B4 1 0 1 0 2 1 185 B4 1 0 4 0 2 1 186 B4 1 0 7 02 1 187 B4 1 0 1, 6 0 2 1 188 B4 1 0 2, 7 0 2 1 189 B4 1 0 4, 9 0 2 1190 B4 1 0 1, 4, 7 0 2 1 191 B4 1 0 0, 2, 4, 6, 8 0 2 1 192 B4 1 0 0, 1,2, 3, 4, 0 2 1 5, 6, 7, 8, 9 193 B4 1 0 1, 3, 5, 7, 9 0 2 1 194 C0 8 1 40 2 7 195 C0 4 0 4 0 2 7 196 C0 4 1 4, 9 0 1 7 197 C0 2 0 4, 9 0 1 7 198C0 2 0 1 0 2 7 199 C0 2 0 4 0 2 7 200 C0 2 0 7 0 2 7 201 C0 1 0 1 0 2 7202 C0 1 0 4 0 1 7 203 C0 1 0 7 0 2 7 204 C0 1 0 1, 6 0 1 7 205 C0 1 02, 7 0 2 7 206 C0 1 0 4, 9 0 1 7 207 C0 1 0 1, 4, 7 0 2 7 208 C0 1 0 0,2, 4, 6, 8 0 2 7 209 C0 1 0 0, 1, 2, 3, 4, 0 2 7 5, 6, 7, 8, 9 210 C0 10 1, 3, 5, 7, 9 0 2 7 211 C2 16 1 4, 9 0 1 2 212 C2 8 1 4, 9 0 1 2 213C2 4 0 4, 9 0 1 2 214 C2 16 1 4 0 2 2 215 C2 8 1 4 0 2 2 216 C2 4 0 4 02 2 217 C2 2 1 2, 6, 9 0 2 2 218 C2 2 0 1 0 2 2 219 C2 2 0 4 0 2 2 220C2 2 0 7 0 2 2 221 C2 1 0 1 0 2 2 222 C2 1 0 4 0 1 2 223 C2 1 0 7 0 2 2224 C2 1 0 1, 6 0 1 2 225 C2 1 0 2, 7 0 2 2 226 C2 1 0 4, 9 0 1 2 227 C21 0 1, 4, 7 0 2 2 228 C2 1 0 0, 2, 4, 6, 8 0 2 2 229 C2 1 0 0, 1, 2, 3,4, 0 2 2 5, 6, 7, 8, 9 230 C2 1 0 1, 3, 5, 7, 9 0 2 2 231 A1/B1 2 0 4, 90 1 7 232 A1/B1 2 0 4 0 2 7 233 A1/B1 1 0 1 0 2 7 234 A1/B1 1 0 4 0 1 7235 A1/B1 1 0 7 0 2 7 236 A1/B1 1 0 1, 6 0 1 7 237 A1/B1 1 0 4, 9 0 1 7238 A1/B1 1 0 1, 4, 7 0 2 7 239 A1/B1 1 0 0, 2, 4, 6, 8 0 2 7 240 A1/B11 0 0, 1, 2, 3, 4, 0 2 7 5, 6, 7, 8, 9 241 A2/B2 2 1 2, 6, 9 0 1 3 242A2/B2 2 0 4 0 2 3 243 A2/B2 1 0 1 0 2 3 244 A2/B2 1 0 4 0 1 3 245 A2/B21 0 7 0 2 3 246 A2/B2 1 0 1, 6 0 1 3 247 A2/B2 1 0 4, 9 0 1 3 248 A2/B21 0 1, 4, 7 0 2 3 249 A2/B2 1 0 0, 2, 4, 6, 8 0 2 3 250 A2/B2 1 0 0, 1,2, 3, 4, 0 2 3 5, 6, 7, 8, 9 251 A3/B3 2 1 2, 6, 9 0 2 2 252 A3/B3 2 0 40 2 2 253 A3/B3 1 0 1 0 2 2 254 A3/B3 1 0 4 0 1 2 255 A3/B3 1 0 7 0 2 2256 A3/B3 1 0 1, 6 0 1 2 257 A3/B3 1 0 4, 9 0 1 2 258 A3/B3 1 0 1, 4, 70 2 2 259 A3/B3 1 0 0, 2, 4, 6, 8 0 2 2 260 A3/B3 1 0 0, 1, 2, 3, 4, 0 22 5, 6, 7, 8, 9

Embodiment 2

Embodiment 2 relates to a method of indicating a PRACH resource index.

FIG. 4 illustrates an example of a method of indicating a PRACH resource(hereinafter, also referred to as a PRACH resource indication method) inan SSB-PRACH mapping period according to an example embodiment.

Referring to FIG. 4, an eNode B and a UE recognize in advance arelationship between an SS/PBCH block index (CSI-RS index based on aCSI-RS-PRACH-CFRA-association configuration) and a PRACH occasion, basedon an upper layer configuration for SSB-PRACH-CFRA-association. Theabove example assumes the following settings.

PRACH configuration period: is set to 10 ms. It is possible to indicateto the UE that the PRACH occasion (time resource) is set per specifictime (e.g., every 10/20/40/80 or 160 ms) based on the correspondingPRACH configuration period.

-   -   The corresponding value range may include one of {10, 20, 40,        80, 160 ms}.    -   A single value is set based on a PRACH configuration index value        by referring to, for example, Table 3.

Actual transmitted SSB (or CSI-RS)-PRACH mapping configuration period:is set to 40 ms. The corresponding parameter may be set to the UE by theeNode B based on an upper layer parameter for a period in which arelationship between the actual transmitted SSB (or CSI-RS) index andthe PRACH occasion is repeatedly applied, or may be predetermined usinga single random value. In the above example, the corresponding period isset to 40 ms and the actual transmitted SSB (or CSI-RS) index and RACHoccasions set within 40 ms may be cyclically mapped to each other withinthe corresponding time domain. Referring to FIG. 4 (e.g., first andsecond ROs for SSB index #0);

a single box: represents a single RO in FIG. 4;

SSB per RO: a number of SSBs per PRACH occasion =½

-   -   Configuration information regarding a number of SSBs capable of        being associated with a single RO    -   The corresponding value range may include one of {⅛, ¼, ½, 1, 2,        4, 8, 16}.

FDM: sets PRACH-FDM, presence or absence of an FDM-based RO in a time inwhich a RO for preamble transmission is present, and a number of ROs forFDM. In the above example, it is set as 2.

-   -   The corresponding value range may include one of {1, 2, 4, 8}.

A number of actual transmitted SSBs: is set to 8. Actual SSBtransmission corresponding to a maximum number L of transmittable SSBsor less may be performed based on upper layer configuration of the eNodeB within the maximum number L of transmittable SSBs. The number ofactual transmitted SSBs may be provided through system information orthrough dedicated RRC signaling to UEs present in a cell in which theeNode B operates in such a manner that the eNode B selects a randomvalue based on a physical location of the cell, beam coveragecorresponding thereto, eNode B antenna capability (e.g., the number ofantennas and antenna configuration (e.g., analogue beam forming ordigital/hybrid beam forming)), and the like.

PRACH resource indicator (K bits) may include an SSB (or CSI-RS) indexand/or RO occasion chances. Through the above configuration method, itis possible to provide the UE with a further flexible preambletransmission resource by indicating a portion of or all of ROs (e.g.,first RO and second RO of FIG. 4) capable of being present in aplurality of time domains associated with a single SSB (or CSI-RS) indexwithin a SSB-PRACH mapping period (e.g., 40 ms) as shown in the exampleof FIG. 4. For example, the eNode B may indicate to the UE that thePRACH resource indicator indicates the SSB (or CSI-RS) index andadditionally indicates a specific RO allowing a CFRA-based preambletransmission among a plurality of ROs associated with the SSB (orCSI-RS) index.

For example, Table 7 may be provided for the above embodiment. That is,the SSB (or CSI-RS) index and ROs associated therewith may be indicatedusing a single PRACH resource index. Also, the SSB index and the ROindex associated therewith may be separately indicated.

TABLE 7 PRACH Allowed PRACH resource SSB index (or CSI-RS) (K bits)index ROs associated SSB (or CSI-RS) index 0 0 Any 1 1 Any 2 2 Any 3 3Any . . . . . . Any 8 0 Even time domain ROs associated with SSB (orCSI-RS) #0 within SSB-PRACH mapping configuration period 9 0 Odd timedomain ROs associated with SSB (or CSI-RS) #0 within SSB-PRACH mappingconfiguration period 10  1 Even time domain ROs associated with SSB(orCSI-RS) #0 within SSB-PRACH mapping configuration period 11  1 Odd timedomain ROs associated with SSB (or CSI-RS) #0 within SSB-PRACH mappingconfiguration period . . . . . . . . .

Referring to the embodiment of Table 7, the eNode B may combine specificRO indices and SSB (or CSI-RS) index within the SSB-PRACH mappingconfiguration period and may indicate CFRA transmission to the UEthrough PDCCH order. Therefore, the eNode B may indicate to the UE theCFRA preamble transmission in all of or a portion of ROs associated witha corresponding SSB index using RO index or specific RO index numbers,such as first/second, as well as even or odd time domain ROs withinTable 7.

TABLE 8 PRACH Allowed PRACH resource SSB (or index CSI-RS) (K bits)index ROs associated SSB (or CSI-RS) index 0 0 Any 1 1 Any 2 2 Any 3 3Any . . . . . . Any 8 0 Even time/Evenfreq. domain ROs associated withSSB (or CSI-RS) #0 within SSB-PRACH mapping configuration period 9 0 Oddtime/Oddfreq. domain ROs associated with SSB (or CSI-RS) #0 withinSSB-PRACH mapping configuration period 10  1 Even time/Evenfreq. domainROs associated with SSB (or CSI-RS) #0 within SSB-PRACH mappingconfiguration period 11  1 Odd time/Odd freq. domain ROs associated withSSB (or CSI-RS) #0 within SSB-PRACH mapping configuration period . . . .. . . . .

Here, although FIG. 4 illustrates that a CFRA preamble transmissionresource is selectively indicated in a time domain, it can be verifiedthat a plurality of ROs is associated with a single SSB in a frequencydomain. In this case, a CFRA preamble index set per SSB index may beused to perform a corresponding preamble transmission in each of FDMedROs. That is, in the embodiment of FIG. 4, an SSB index and a timedomain RO are indicated through a PRACH resource index within a DCIformat. Here, the eNode B additionally indicates a preamble index valueto the UE through a preamble index field. The eNode B may indicate aCFRA preamble transmission resource in a different time domain based onsuch indication information, however, may not indicate an additionalCFRA preamble transmission in a frequency domain. Accordingly, when aplurality of ROs associated with the same SSB is present in thefrequency domain as described above (e.g., SSB per RO<1), the preambletransmission needs to be performed in the plurality of ROs. Therefore,the UE may unnecessarily perform a plurality of preamble transmissions,which may cause interference. Accordingly, the following proposedadditional embodiment relates to signaling for PDCCH order byadditionally indicating a RO resource in a frequency domain in a DCIformat.

FIG. 5 illustrates another example of a PRACH resource indication methodin an SSB-PRACH mapping period according to an example embodiment. Here,the example of FIG. 5 may be set as follow:

-   -   PRACH configuration period: is set to 10 ms.    -   Actual transmitted SSB (or CSI-RS)-PRACH mapping configuration        period: 40 ms    -   SSB per RO: a number of SSBs per PRACH occasion=¼    -   PRACH-FDM=4

Referring to FIG. 5, a CFRA preamble transmission in a specific ROwithin a single SSB-PRACH mapping period is indicated based oninformation of SSB index=0 (or CSI-RS index), frequency domain ROindex=even, and time index RO index=odd.

FIG. 6 illustrates another example of a PRACH resource indication methodin an SSB-PRACH mapping period according to an example embodiment. Here,the example of FIG. 6 may be set as follows:

-   -   PRACH configuration period: is set to 10 ms.    -   Actual transmitted SSB (or CSI-RS)-PRACH mapping configuration        period: 40 ms    -   SSB per RO: a number of SSBs per PRACH occasion=½    -   PRACH-FDM=1    -   Number of transmitted SSBs: is set to 4.

Referring to FIG. 6, a CFRA preamble transmission in a specific ROwithin a single SSB-PRACH mapping period is indicated based oninformation of SSB index=1 (or CSI-RS index), frequency domain ROindex=even, and time index RO index=odd.

FIG. 7 illustrates another example of a PRACH resource indication methodin an SSB-PRACH mapping period according to an example embodiment. Here,the example of FIG. 7 may be set as follows:

-   -   PRACH configuration period: is set to 10 ms.    -   Actual transmitted SSB (or CSI-RS)-PRACH mapping configuration        period: 40 ms    -   SSB per RO: number of SSBs per PRACH occasion=2    -   PRACH-FDM=1    -   Number of transmitted SSBs: is set to 4.

Referring to FIG. 7, a CFRA preamble transmission in a specific ROwithin a single SSB-PRACH mapping period is indicated based oninformation of SSB index=3 (or CSI-RS index) only. Therefore, if upperlayer parameter SSB per RO: number of SSBs per PRACH occasion ≥1 (i.e.,SSB per RO=1, 2, 4, 8 or 16), only an SSB index is indicated through aDCI format as shown in FIG. 7. Otherwise (i.e., SSB per RO=⅛, ¼ or ½),the CFRA preamble transmission in the specific RO is indicated throughthe SSB index, time/frequency domain RO index proposed in FIGS. 4 to 6.

A PRACH resource index indicates an “SSB index” and a “RO index” andthereby indicates the CFRA preamble transmission only in a specific ROwithin the SSB-PRACH mapping period. Here, a number of bits for the SSBindex may be determined based on the number of actual transmitted SSBsand a number of bits for the RO index may be determined based on aPRACH-FDM value.

For example, the eNode B and the UE may assume the same case in which,if the number of actual transmitted SSB=12 through upper layerconfiguration, the SSB index of 4 bits may be transmitted and if thePRACH-FDM=8, the RO index of 3 bits may be transmitted within the DCIformat.

FIG. 8 illustrates another example of a PRACH resource indication methodin an SSB-PRACH mapping period according to an example embodiment. Here,the example of FIG. 8 may be set as follows:

-   -   PRACH configuration period: is set to 10 ms.    -   Actual transmitted SSB(or CSI-RS)-PRACH mapping configuration        period: 40 ms    -   SSB per RO: a number of SSBs per PRACH occasion=½    -   PRACH-FDM=2    -   Number of transmitted SSBs: is set to 8.

As a feature of the method of FIG. 8, RO indexing may be performed persection in which all of indices of actual transmitted SSBs are indexedwith a RO at least once.

The “PRACH resource index indicates the RO index” and thereby indicatesthe CFRA preamble transmission only in the specific RO within theSSB-PRACH mapping period.

FIG. 9 illustrates another example of a PRACH resource indication methodin an SSB-PRACH mapping period according to an example embodiment. Here,the example of FIG. 9 may be set as follows:

-   -   PRACH configuration period: is set to 10 ms.    -   Actual transmitted SSB (or CSI-RS)-PRACH mapping configuration        period: 40 ms    -   SSB per RO: a number of SSBs per PRACH occasion=½    -   PRACH-FDM=2    -   Number of transmitted SSBs: is set to 8.

As a feature of the method of FIG. 9, RO indexing may be performed persection in which all of indices of actual transmitted SSBs are indexedwith a RO at least once.

In the proposed embodiments, a plurality of pieces of indicatorinformation, for example, all of an SSB index, a RO index, a specifictime information index, and the like, indicating a CFRA preambletransmission resource may be joint coded as a single indicator and maybe present within a DCI format as an independent control informationfield. Also, as described above, a number of bits of correspondingfields may vary based on an upper layer configuration.

FIG. 10 illustrates an example of a PRACH resource indication methodaccording to an example embodiment.

In the proposed embodiments, a plurality of pieces of indicatorinformation, for example, all of an SSB index, a RO index, a specifictime information index, and the like, indicating a CFRA preambletransmission resource may be joint coded as a single indicator and maybe present within a DCI format as an independent control informationfield. Also, as described above, a number of bits of correspondingfields may vary based on an upper layer configuration.

As another embodiment, referring to FIG. 10, the corresponding UE mayconsider a case in which a relationship between an SS/PBCH block index(i.e., SSB) (and/or CSI-RS index) and a PRACH occasion (i.e., ROs infollowing Figure) index is not established (i.e., a case in which anupper layer configuration for SSB-PRACH-CFRA-association orCSI-RS-PRACH-CFRA-association is absent). Here, since the configurationfor the SSB-PRACH association is absent, information on at least the SSBindex is not valid. Accordingly, the specific RO may be indicated usinga RO index value only.

Embodiment 3

Embodiment 3 may consider a case in which a plurality of CFRA preambletransmissions is set.

Here, FIGS. 11 and 12 illustrate examples of a PRACH resource indicationmethod for a UE to which four preamble transmissions are set accordingto an embodiment.

Offset values implicitly determined in SSB index and/or RO indexinformation, which is considered in the methods discussed above as thePRACH resource indication method for the plurality of CFRA preambletransmissions, are assumed as a resource for additional preambletransmission. That is, when the plurality of CFRA preamble transmissionsis set to the UE, the eNode B may perform a resource indication for afirst preamble transmission based on an SSB index and/or RO index valueindicated through the proposed method and may add offset values of theSSB index and/or RO index for the first preamble transmission andthereby indicate a corresponding resource from a resource for a secondpreamble transmission.

For example, referring to FIG. 11, when four CFRA preamble transmissionsare set to a single UE before a single RAR window is terminated andSSB-PRACH-CFRA-association or CSI-RS-PRACH-CFRA-association is set tothe UE, predetermined values may be used as additional offset values tothe indicated SSB index (or CSI-RS index) value through the proposedmethods.

-   -   1st preamble transmission: indicated SSB index (or CSI-RS        index),    -   2nd preamble transmission: indicated SSB index (or CSI-RS        index)+1,    -   3rd preamble transmission: indicated SSB index (or CSI-RS        index)+2,    -   4th preamble transmission: indicated SSB index (or CSI-RS        index)+3

Accordingly, the CFRA preamble transmissions may be performed on ROsrespectively associated with the four indicated SSB index, SSB index+1,SSB index+2, and SSB index+3 based on the s indicated SSB index, SSBindex+1, SSB index+2, and SSB index+3. Through the above indicationmethod, the four preamble transmissions enable different uplink beamtransmissions, which assists the eNode B to receive a preamble of thecorresponding UE.

Accordingly, referring to FIG. 12, additional offset values may beconsidered for the plurality of preamble transmissions based on theresource indication method proposed in embodiment 3. Alternatively, theadditional offset values may be considered for the plurality of preambletransmissions based on a preamble index indicated by a preamble indexfield.

-   -   1st preamble transmission: indicated RO index,    -   2nd preamble transmission: indicated RO index +1,    -   3rd preamble transmission: indicated RO index +2,    -   4th preamble transmission: indicated RO index +3 or    -   1st preamble transmission: indicated Preamble index,    -   2nd preamble transmission: indicated Preamble index +1,    -   3rd preamble transmission: indicated Preamble index +2,    -   4th preamble transmission: indicated Preamble index +3

Offset values considered in the proposed method may be predetermined asin the above example. Alternatively, the offset values may be setthrough an upper layer configuration. Accordingly, when the upper layerconfiguration is present, a resource for a corresponding preambletransmission may be indicated based on the offset values indicated inthe upper layer from a transmission resource for the second preambletransmission.

As another method, the offset values may be applied based on a RO indexinstead of using an SSB index.

Preamble Index—6 Bits

Present within a DCI format for PDCCH order for the eNode B to indicatea total of 64 available preamble indices to the UE.

BWP Indicator—1 or 2 Bits

indicates a BWP for CFRA preamble transmission as a bandwidth partindicator and indicates a BWP used for a corresponding CFRA preambletransmission among BWPs set through an upper layer.

UL/SUL Indicator—1 Bit

indicates whether to perform a CFRA preamble transmission in a normal ULcarrier or a supplement UL (SUL) carrier through a corresponding fieldwhen the SUL carrier is set to the UE.

A wireless device may receive, from a base station, one or more messagescomprising downlink control information (DCI) associated with a DCIformat. The wireless device may determine that a first field of the DCIcorresponds to a predefined value, determine that, based on the firstfield corresponding to the predefined value, the DCI is for a randomaccess procedure associated with a physical downlink control channel(PDCCH) order, and determine, based on the determining that the DCI isfor a random access procedure associated with a PDCCH order and based ona plurality of fields of the DCI, a random access channel (RACH)occasion. The wireless device may transmit, based on the RACH occasion,a random access preamble. The plurality of fields of the DCI maycomprise an SS/PBCH block index field having a value indicating theSS/PBCH block and an index field having a value indicating one or moreRACH occasions. The wireless device may receive information associatedwith a location of one or more SS/PBCH blocks. The wireless device maydetermine, from an SS/PBCH block indicated by the value of the SS/PBCHblock index field, the RACH occasion. The first field may correspond toa frequency domain resource assignment field. The DCI format may be DCIformat 1_0 associated with a physical downlink shared channel (PDSCH)scheduling. The wireless device may determine the DCI based on CellRadio Network Temporary Identifier (C-RNTI). The DCI may comprise one ormore of an identifier for the DCI format, a random access preambleindex, or an uplink/supplemental uplink (UL/SUL) indicator.

A wireless device may receive, from a base station, one or more messagescomprising downlink control information (DCI). The wireless device maydetermine that the DCI corresponds to DCI format 1_0, determine that,based on a first field of the DCI format 1_0, the DCI is for a randomaccess procedure associated with a physical downlink control channel(PDCCH) order, and determine, based on a synchronization signal/physicalbroadcast channel (SS/PBCH) block index field of the DCI and based on anindex field associated with one or more random access channel (RACH)occasions, a RACH occasion. The wireless device may transmit, based onthe RACH occasion, a random access preamble. The wireless device mayreceive information associated with a location of one or more SS/PBCHblocks. The wireless device may determine, from an SS/PBCH blockindicated by a value of the SS/PBCH block index field, the RACHoccasion. The first field may correspond to a frequency domain resourceassignment field. The DCI may comprise one or more of an identifier forthe DCI format, a random access preamble index, or anuplink/supplemental uplink (UL/SUL) indicator. The wireless device maydetermine the DCI based on Cell Radio Network Temporary Identifier(C-RNTI). The wireless device may receive second DCI corresponding tothe DCI format 1_0. The wireless device may determine that a frequencydomain resource assignment field has a value different from a predefinedvalue, which is associated with the random access procedure. Thewireless device may retrieve, from the second DCI, information of aphysical downlink shared channel (PDSCH) scheduling.

A base station may determine a random access channel (RACH) occasion fora wireless device. The RACH occasion may be associated with asynchronization signal/physical broadcast channel (SS/PBCH) block. Thebase station may generate downlink control information (DCI)corresponding to a DCI format. The DCI may comprise: a first fieldhaving a predefined value indicating that the DCI is for a random accessprocedure associated with a physical downlink control channel (PDCCH)order; an SS/PBCH block index field having a value indicating theSS/PBCH block; and an index field having a value indicating one or moreRACH occasions. The RACH occasion for the wireless device may beindicated by the values of the SS/PBCH block index field and the indexfield. The base station may transmit, to the wireless device, the DCI;and may receive, from the wireless device and based on the RACHoccasion, a random access preamble. The base station may transmitinformation associated with a location of one or more SS/PBCH blocks.The base station may scramble the DCI based on Cell Radio NetworkTemporary Identifier (C-RNTI). The DCI may comprise one or more of anidentifier for the DCI format, a random access preamble index, or anuplink/supplemental uplink (UL/SUL) indicator. The RACH occasion may bewithin an SS/PBCH block indicated by the value of the SS/PBCH blockindex field. The first field may correspond to a frequency domainresource assignment field. The DCI format may be DCI format 1_0associated with a physical downlink shared channel (PDSCH) scheduling.The base station may generate second DCI for a PDSCH scheduling. Thesecond DCI may comprise the first field having a value different fromthe predefined value. The base station may transmit, to the wirelessdevice, the second DCI.

FIG. 13 is a block diagram illustrating a UE and an eNode B.

Referring to FIG. 13, a base station device 1300 may include a processor1310, an antenna device 1320, a transceiver 1330, and a memory 1340.

The processor 1310 may perform baseband-related signal processing andmay include an upper layer processing 1311 and a physical (PHY) layerprocessing 1315. The upper layer processing 1311 may process anoperation of a Medium Access Control (MAC) layer, a Radio ResourceControl (RRC) layer, or more upper layer. The PHY layer processing 1315may process an operation (e.g., uplink (UL) received signal processingand downlink (DL) transmission signal processing) of a PHY layer. Theprocessor 1310 may control the overall operation of the base stationdevice 1300 in addition to performing the baseband-related signalprocessing.

The antenna device 1320 may include at least one physical antenna. Ifthe antenna device 1320 includes a plurality of antennas, multiple inputmultiple output (MIMO) transmission and reception may be supported. Thetransceiver 1330 may include a radio frequency (RF) transmitter and anRF receiver. The memory 1340 may store operated information of theprocessor 1310 and software, an operating system (OS), an application,etc., associated with an operation of the base station device 1300, andmay include a component, for example, a buffer.

The processor 1310 of the base station device 1300 may be configured toimplement an operation of a base station in the example embodimentsdisclosed herein.

Referring again to FIG. 13, a terminal device 1350 may include aprocessor 1360, an antenna device 1370, a transceiver 1380, and a memory1390.

The processor 1360 may perform baseband-related signal processing andmay include an upper layer processing 1361 and a PHY layer processing1365. The upper layer processing 1361 may process an operation of a MAClayer, an RRC layer, or more upper layer. The PHY layer processing 1365may process an operation (e.g., UL received signal processing and DLtransmission signal processing) of a PHY layer. The processor 1360 mayalso control the overall operation of the terminal device 1350 inaddition to performing baseband-related signal processing.

The antenna device 1370 may include at least one physical antenna. Ifthe antenna device 1370 includes a plurality of antennas, MIMOtransmission and reception may be supported. The transceiver 1380 mayinclude an RF transmitter and an RF receiver. The memory 1390 may storeoperated information of the processor 1360 and software, an OS, anapplication, etc., associated with an operation of the terminal device1350, and may include a component, for example, a buffer.

The processor 1360 of the terminal device 1350 may be configured toimplement an operation of a terminal in the example embodiment disclosedherein.

The processors may include an application-specific integrated circuit(ASIC), another chipset, a logic circuit, and/or a data processingdevice. The memories may include a Read-Only Memory (ROM), a RandomAccess Memory (RAM), a flash memory, a memory card, a storage mediumand/or another storage device. The RF units may include a basebandcircuit for processing a wireless signal. When an embodiment is embodiedas software, the described scheme may be embodied as a module (process,function, or the like) that executes the described function. The modulemay be stored in a memory, and may be executed by a processor. Thememory may be disposed inside or outside the processor, and may beconnected to the processor through various well-known means.

In the described exemplary system, although methods are described basedon a flowchart as a series of steps or blocks, aspects are not limitedto the sequence of the steps and a step may be executed in a differentorder or may be executed in parallel with another step. In addition, itis apparent to those skilled in the art that the steps in the flowchartare not exclusive, and another step may be included or one or more stepsof the flowchart may be omitted without affecting the scope of thepresent disclosure.

What is claimed is:
 1. A method comprising: receiving, by a wirelessdevice from a base station, one or more messages comprising downlinkcontrol information (DCI) associated with a DCI format; determining thata first field of the DCI corresponds to a predefined value; determiningthat, based on the first field corresponding to the predefined value,the DCI is for a random access procedure associated with a physicaldownlink control channel (PDCCH) order; determining, based on thedetermining that the DCI is for a random access procedure associatedwith a PDCCH order and based on a plurality of fields of the DCI, arandom access channel (RACH) occasion associated with a synchronizationsignal/physical broadcasting channel (SS/PBCH) block, wherein theplurality of fields of the DCI comprise: an SS/PBCH block index fieldhaving a value indicating the SS/PBCH block; and a RACH index fieldhaving a value indicating one or more RACH occasions; determining, basedon the SS/PBCH block index field and the RACH index field, the RACHoccasion associated with the SS/PBCH block; and transmitting, based onthe RACH occasion associated with the SS/PBCH block, a random accesspreamble.
 2. The method of claim 1, further comprising: receivinginformation associated with a location of one or more transmissionSS/PBCH blocks, wherein determining the RACH occasion comprisesdetermining, based on the SS/PBCH block indicated by the value of theSS/PBCH block index field, the RACH occasion.
 3. The method of claim 1,wherein the first field corresponds to a frequency domain resourceassignment field of DCI format 1_0.
 4. The method of claim 1, whereinthe DCI format is DCI format 1_0 associated with a physical downlinkshared channel (PDSCH) scheduling.
 5. The method of claim 1, furthercomprising determining the DCI based on Cell Radio Network TemporaryIdentifier (C-RNTI).
 6. The method of claim 1, wherein the DCI comprisesan uplink/supplemental uplink (UL/SUL) indicator associated with therandom access preamble.
 7. The method of claim 2, further comprising:receiving, from the base station, configuration information comprisingone or more of: a physical RACH (PRACH) configuration period; atransmission SS/PBCH block-PRACH mapping configuration period; or anumber of SS/PBCH blocks per RACH occasion.
 8. The method of claim 1,further comprising: determining, based on the determining that the DCIis for a random access procedure associated with a PDCCH order, anuplink/supplemental uplink (UL/SUL) indicator of the plurality of fieldsof the DCI, wherein the transmitting the random access preamblecomprises transmitting, based on the UL/SUL indicator, the random accesspreamble via an SUL carrier.
 9. A method comprising: determining, by abase station, a random access channel (RACH) occasion for a wirelessdevice, wherein the RACH occasion is associated with a synchronizationsignal/physical broadcast channel (SS/PBCH) block; generating downlinkcontrol information (DCI) corresponding to a DCI format, the DCIcomprising: a first field having a predefined value indicating that theDCI is for a random access procedure associated with a physical downlinkcontrol channel (PDCCH) order; an SS/PBCH block index field having avalue indicating the SS/PBCH block; and an index field having a valueindicating one or more RACH occasions, wherein the RACH occasion for thewireless device is indicated by the values of the SS/PBCH block indexfield and the index field; transmitting, to the wireless device, theDCI; and receiving, from the wireless device and based on the RACHoccasion, a random access preamble.
 10. The method of claim 9, furthercomprising: transmitting information associated with a location of oneor more SS/PBCH blocks.
 11. The method of claim 9, wherein the firstfield corresponds to a frequency domain resource assignment field of DCIformat 1_0.
 12. The method of claim 9, wherein the DCI format is DCIformat 1_0 associated with a physical downlink shared channel (PDSCH)scheduling.
 13. The method of claim 12, further comprising: generatingsecond DCI for a PDSCH scheduling, wherein the second DCI comprises afield having a value different from the predefined value; andtransmitting, to the wireless device, the second DCI.
 14. The method ofclaim 9, further comprising scrambling the DCI based on Cell RadioNetwork Temporary Identifier (C-RNTI).
 15. The method of claim 9,wherein the DCI comprises an uplink/supplemental uplink (UL/SUL)indicator associated with the random access preamble.
 16. A methodcomprising: receiving, by a wireless device from a base station, one ormore messages comprising downlink control information (DCI); determiningthat the DCI corresponds to DCI format 1_0; determining that, based on avalue of a first field of the DCI format 1_0, the DCI is for a randomaccess procedure associated with a physical downlink control channel(PDCCH) order; determining, based on a synchronization signal/physicalbroadcast channel (SS/PBCH) block index field of the DCI and based on anindex field associated with one or more random access channel (RACH)occasions, a RACH occasion associated with an SS/PBCH block indicated bythe SS/PBCH block index field; and transmitting, based on the RACHoccasion associated the SS/PBCH block, a random access preamble.
 17. Themethod of claim 16, further comprising: receiving information associatedwith a location of one or more SS/PBCH blocks, wherein determining theRACH occasion comprises determining, based on the SS/PBCH blockindicated by a value of the SS/PBCH block index field, the RACHoccasion.
 18. The method of claim 16, wherein the first fieldcorresponds to a frequency domain resource assignment field.
 19. Themethod of claim 16, further comprising: receiving second DCIcorresponding to the DCI format 1_0; determining that a frequency domainresource assignment field has a value different from a predefined value,wherein the predefined value is associated with the random accessprocedure; and retrieving, from the second DCI, information of aphysical downlink shared channel (PDSCH) scheduling.
 20. The method ofclaim 16, further comprising determining the DCI based on Cell RadioNetwork Temporary Identifier (C-RNTI).
 21. The method of claim 16,wherein the DCI comprises an uplink/supplemental uplink (UL/SUL)indicator associated with the random access preamble.